// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
#nullable enable
 
using Microsoft.AspNetCore.Mvc.ModelBinding.Validation;
 
namespace Microsoft.AspNetCore.Mvc.ModelBinding.Binders;
 
/// <summary>
/// <see cref="IModelBinder"/> implementation to bind models of type <see cref="CancellationToken"/>.
/// </summary>
public class CancellationTokenModelBinder : IModelBinder
{
    /// <inheritdoc />
    public Task BindModelAsync(ModelBindingContext bindingContext)
    {
        ArgumentNullException.ThrowIfNull(bindingContext);
 
        // We need to force boxing now, so we can insert the same reference to the boxed CancellationToken
        // in both the ValidationState and ModelBindingResult.
        //
        // DO NOT simplify this code by removing the cast.
        var model = (object)bindingContext.HttpContext.RequestAborted;
        bindingContext.ValidationState.Add(model, new ValidationStateEntry() { SuppressValidation = true });
        bindingContext.Result = ModelBindingResult.Success(model);
 
        return Task.CompletedTask;
    }
}